[casstony]

I just recently started playing with images again and found that the NP101 at f/5.4 produces much more red in the stacked image than my FC100 at f/6 with WO 0.8x reducer.

The two images are cropped parts of Carina, both 30 x 2 minutes, taken with a Nikon D5600, ISO 400 and IDAS P2.
The redder image is the NP (also softer because of crappy weather conditions).

Is the extra red simply due to the faster f ratio (f5.4 vs f6) or is it because of the different telescopes/reducer?